Resistance Changes not working with Ant+ ... Works with Bluetooth

On zwift with the pc client and my wahoo kickr core resistance adjusts to the current grade when connected through bluetooth however it does work through ant. It took me several hours to figure out ant was the issue. Should I just ignore the issue and use bluetooth for the smart trainer or what?


Are you using the ant+ fec option?


I having the same issue with a Tacx Neo 2t. Everything is up to date. Ant+ works on other apps, but resistance will not work in Zwift. I have tried everything I can think of and still can’t figure out what the issue is.

did you pair as Power source and controllable, also you should use ANT+ Fe-c

Paired the power, cadence, and trainer all using FE-C. The neo 2t has lights on the trainer that light-up when a bluetooth and/or Ant+ connection is established. When I pair via bluetooth in Zwift, the bluetooth light lights-up. When I pair via Ant+ in Zwift, the Ant+ light does not light-up.

If I go into TrainerRoad and pair via Ant+, the Ant+ light lights-up. This would lead me to believe that the issue is isolated to Zwift not properly pairing with Ant+.

I’m having very similar problems with a Kickr Snap. See the discussion thread entitled “No resistance changes from Zwift” in this forum taking place right now as well.

Thanks for the suggestion. I wonder if the dongle is just not up to snuff and has dropouts.

I highly doubt it is a hardware/dongle issue, given that my Ant+ works perfectly fine while using the TrainerRoad PC app. I am thinking that the latest update from zwift has killed Ant+ in some way.

TrainerRoad is a very different type of app, and doesn’t have to try and calculate exactly where you are on the road many times every second, based on your power data and other factors.

It’s entirely possible that an app like TrainerRoad can handle patchy ANT+ transmission much better than Zwift.

The transmission rate is the transmission rate. I don’t think Zwift is requiring different Ant+ requirements over TrainerRoad, since the requirements are directly set in the Ant+ protocol.

Still even if it was different requirements, that still would not explain why ERG mode via Ant+ in zwift will not work–resistance or ERG. Both TrainerRoad and Zwift are going to essentially operate the same in ERG mode settings. Even pairing power/cadence in Ant+ in Zwift does not illuminate my 2T’s Ant+ status light.

Given the sloppy programing, feature updates, and UI experience in Zwift; I would put my money on this being a Zwift issue.

OK, I am not an expert here but this may be something to look at. ANT+ has different drivers that are installed on your PC when you first plug in the dongle.

The drivers installed use different hardware. The ANTUSB1 uses an SiLabs based driver and the ANTUSB-m and ANTUSB2 uses a LibUsb-Win32 based driver. It cold be that Zwift will only work with ANTUSB-m or ANTUSB2 while trainer road will work with the older driver. So how do you know which ANT dongle you have? The version of the USB stick is printed on the back of the plastic case. Otherwise the version can be determined by using the Device Manager.

Access the windows device manager by navigating to Control Panel > System > Device Manager. In the manager, ANTUSB2 sticks are called “ANT USB Stick 2”, under the “libusb-win32 devices” node. ANTUSB1 sticks are either called “ANT USB Device” or “ANT USB Stick”, under the “Universal Serial Bus Controllers” node.

To reinstall the drivers:

ANTUSB-m and ANTUSB2 drivers:
The ANTUSB-m and ANTUSB2 Stick drivers can be uninstalled via Windows’ Device Manager, then reinstalled by simply re-inserting the USB device and allowing windows update to download the drivers. Alternatively, the drivers could be downloaded from the website here and installed manually.

ANTUSB1 drivers:
Re-installing the ANTUSB1 drivers is not always a trivial procedure. To do this properly, the old ANTUSB1 driver must first be completely removed from the system. Unfortunately, this is not as easy as uninstalling the driver via Device Manager. To completely remove the ANTUSB1 driver in Windows XP, please follow the technical note “Uninstalling USB1 Drivers” . Once the old drivers are completely removed, the new drivers may be installed using the standard procedure.

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Good find. I will check the driver and report back. Also, you’re still rocking Windows XP? Impressive.

I’m on 10 now.